Myocardial infarction in the familial forms of hypertriglyceridemia.

Among 74 hypertriglyceridemic patients who were referred for study because of hypertriglyceridemia, family investigations detected 19 with familial hypertriglyceridemia and 24 with familial combined hyperlipidemia. The frequency of myocardial infarction among adult living hyperlipidemic relatives of patients with familial combined hyperlipidemia was 17.5% (10/57). Five of these relatives had their infarct between the ages of 40 and 50 yr of age, and five before the age of 40 yr. The frequency of myocardial infarction in living hyperlipedemic relatives with familial hypertriglyceridemia was 4.7% (2/43) and was similar to the frequency of myocardial infarction among normolipidemic relatives (4.5%) or among spouse controls (5.2%). Mortality data due to myocardial infarction among relatives of index patients failed to contribute meaningful information.